Figure 3.

Deuterium-labelled trimethylamine-N-oxide production from orally ingested deuterium-labelled choline or betaine in mice and an obligatory role for gut flora in generation of plasma trimethylamine-N-oxide. (A) d9-choline or (B) d9-betaine was administered by gastric gavage in C57BL/6J mice, and plasma levels of d9-trimethylamine-N-oxide were monitored at the indicated times as described under ‘Methods’ section. (D) Plasma concentrations of d9-choline or (E) d9-betaine were determined by LC/MS/MS following oral ingestion of d9-choline or d9-betaine, respectively, as described under ‘Methods’ section. (C and F) d9-trimethylamine-N-oxide production and plasma d9-betaine concentration after oral d9-betaine administration in mice following suppression of gut flora with antibiotics (3 weeks). Data are presented as means ± standard error from two (A and D) and three (B and C, E and F) female mice.